Growth hormone treatment strategy for short children born small for gestational age

Several studies performed in the last 15 years have shown that growth hormone (GH) induces a profound catch-up in height in short children born small for gestational age (SGA). We know from more recent studies that final height can be normalized through GH treatment. In Europe, GH is now a recognized indication, enabling treatment of short children born SGA. Treatment is given to the most severe growth-retarded children after the age of 4 years. A dose of 0.035 mg/kg per day is recommended. However, in our opinion a higher dose would be more efficient in very short children, especially if they are treated later in childhood.     

Growth hormone treatment in short Japanese children born small for gestational age

Recent reports have shown that high-dose growth hormone (GH) treatment in short children born with small for gestational age (SGA) resulted in a pronounced acceleration of linear growth. We describe the results of multicenter trials of recombinant human GH (rhGH) treatment in short SGA children in Japan. Two clinical studies were performed and the results were combined. Study 1 comprised 104 SGA children and study 2 comprised 61 SGA children. The patients were divided into three groups: group 1 consisted of 20 patients (13 boys and 7 girls) who received rhGH 25 microg/kg per day six or seven times per week in the first year and 50 microg/kg per day in the second year and thereafter; group 2 consisted of 48 patients (28 boys, 20 girls) who received rhGH 45/50 microg/kg per day; group 3 consisted of 44 patients (28 boys, 16 girls) who received 90/100 microg/kg per day. The mean increments in height SDS were 0.46, 0.67 and 0.94 SD in boys and 0.49, 0.79 and 0.93 SD in girls in groups 1, 2 and 3, respectively. The mean increment in height SDS at 2 years in group 3 was significantly greater than that in group 1, but it was not significantly different from that in group 2 in boys and girls. Our data demonstrated that high-dose GH administration significantly improved height velocity and height SDS in short SGA children. Additional studies are necessary to optimize a long-term GH treatment regimen and combined luteinizing hormone releasing hormone analog treatment for final height. Careful observation is also necessary to assess the metabolic effects of high-dose GH, especially on carbohydrate metabolism.     

Growth hormone therapy for short children born small for gestational age

Children born small for gestational age may demonstrate continued growth retardation, resulting in persistent short stature. In the majority of the cases, this is linked with abnormal growth hormone secretion and also abnormal insulin-like growth factor levels. This review discusses the treatment of such children with recombinant human growth hormone. It illustrates the importance of starting therapy early, the dose-dependent response, and the advantages of continuous therapy and describes safety considerations.     

Growth hormone therapy in short children born small for gestational age

There is still a lack of data from randomized, controlled, long-term studies of growth hormone (GH) treatment in children born small for gestational age (SGA), but the available evidence indicates consistently that GH therapy is a valid growth-promoting treatment in these children, particularly if started early. Whilst side effects appear uncommon, ongoing surveillance is required and treated children should be monitored for changes in glucose homeostasis, lipid profiles and blood pressure, especially during puberty. We provide an update on the safety and efficacy of GH treatment in short children born SGA.     

Serum leptin in short children born small for gestational age: dose-dependent effect of growth hormone treatment

OBJECTIVE: To study the effects of different regimens of growth hormone (GH) treatment on serum leptin levels in 78 short prepubertal children born small for gestational age (SGA). METHODS: The children were originally included in two independent multicenter trials, one in Belgium and one in the Nordic countries. SGA children were randomized either to remain untreated or to be treated with GH at a daily dose of 0.1, 0.2 or 0.3 IU/kg for 2 years. Thereafter, treatment was continued for another 2 years in the Nordic children, whereas it was discontinued in the Belgian children. RESULTS: In the GH treatment groups, a significant dose-dependent decrease in leptin levels was found during the first year of therapy, with a mean decrease of 13, 23 and 32% in the groups receiving GH at 0.1, 0.2 and 0.3 IU/kg, respectively. When high-dose treatment was interrupted, serum leptin increased within 1 year to pretreatment levels. CONCLUSION: Serum leptin levels in short children born SGA are transiently reduced by GH treatment in a dose-dependent fashion. The most pronounced changes in serum leptin were documented within the first year after initiation and withdrawal of high-dose GH treatment.     

Intermittent recombinant growth hormone treatment in short children born small for gestational age: four-year results of a randomized trial of two different treatment regimens

BACKGROUND: Treatment of short children born small for gestational age SGA with recombinant human growth hormone r-hGH increases growth velocity during childhood. As in other indications, the growth velocity in these patients is more marked during the first year of treatment and then decreases. This study was undertaken to evaluate the efficacy of different r-hGH treatment schedules (67 microg/kg/day in a discontinuous or continuous regimen) during the second year of r-hGH treatment by comparing height velocity changes and total gain of height over a 4-year period. METHODS: 58 growth-retarded SGA children aged 2-5 years were randomized to a TOTO regimen (4 years alternating treatment (T) and observation (O), n = 30) or a TTOO regimen (2 years' treatment, followed by 2 years' observation, n = 28). Height velocity HV and total height gain were assessed during the 4-year study. RESULTS: In both groups, HV and HV standard deviation score HV-SDSCA increased during treatment and decreased during observation periods. Interruption of treatment in the TOTO group did not result in a better gain in height standard deviation score H-SDSCA when compared with the TTOO group. After 4 years of study, the gain in H-SDSCA was 1.4 + or - 01 in the TOTO group and 1.6 + or - 0.2 in the TTOO group leading to a mean height of -2.0 + or - 1.0 SDS and -2.0 + or - 0.8 SDS, respectively. The rate of bone maturation was similar in the two groups. CONCLUSIONS: In short SGA children, TOTO and TTOO regimens produced significant improvements in growth during r-hGH treatment. However, treatment interruption after 1 year did not influence the overall gain in height SDS when compared with 2 years' continuous treatment.     

Babies born small for gestational age: insulin sensitivity and growth hormone treatment

Epidemiological studies have identified an association between size at birth and adult risk for type 2 diabetes mellitus and cardiovascular disease. In contemporary populations, children who are relatively small at birth and show rapid infancy weight gain are at greatest risk for the development of childhood obesity, increased visceral fat and insulin resistance: possible early markers of adult disease risk. Individuals presenting to growth clinics with short stature and a history of low birthweight will not have shown post-natal catch-up growth and may be a very heterogeneous group. Nevertheless, there are some data to suggest that as a group they are insulin resistant with decreased lean mass. Growth hormone treatment leads to reversible worsening of the insulin resistance, and short-term data do not indicate an increased risk for type 2 diabetes. However, further long-term follow-up is required, and particular care should be taken in monitoring children with a strong family history of type 2 diabetes and those from ethnic groups in which there is a high background prevalence of the disease.     

Efficacy and safety of long-term continuous growth hormone treatment of children born small for gestational age

Twelve years of growth hormone (GH) therapy of short children born small for gestational age (SGA) have demonstrated that GH is an effective and well-tolerated therapy. Most children will reach a normal adult height (AH). AH of 55 SGA adolescents was comparable for those treated with a GH dose of 1 or 2 mg/m2 (approximately 0.033 or 0.066 mg/kg) per day, mean (SD) AH SDS being -1.2 (0.7) and -0.8 (0.7), respectively. GH therapy had no influence on the age at onset, the progression of puberty, duration of puberty and pubertal height gain. GH therapy induced higher fasting and glucose-stimulated insulin levels after 1 and 6 years, but 6 months after GH stop, all levels returned to normal. At baseline mean systolic blood pressure was significantly increased, but both systolic and diastolic blood pressure decreased significantly during 6 years of GH and remained so after GH stop. GH therapy demonstrated a beneficial effect on serum lipid profiles, body composition, bone mineral density and head growth. Treatment with 2 mg GH/m2 per day induced mean serum IGF-I levels of +2 SDS, whereas IGF-I levels remained within the normal range with 1 mg GH/m2 per day. In conclusion, long-term GH therapy of short SGA children with 1 mg/m2 per day appears to be effective and safe. Since the future consequences of high serum IGF-I levels during long-term GH therapy with 2 mg/m2 per day are as yet unknown, it seems safer to treat short prepubertal SGA children with a GH dose of 1 mg/m2 per day when children are to be treated continuously for many years.     

Effects of growth hormone treatment on cognitive function and head circumference in children born small for gestational age

Short stature is not the only problem faced by children born small for gestational age (SGA). Being born SGA has also been associated with lowered intelligence, poor academic performance, low social competence and behavioural problems. This paper summarizes the results of a randomized, double-blind, growth hormone (GH) dose-response study (1 or 2 mg/m2/day [ approximately 0.035 or 0.07 mg/kg/day]) on growth, intelligence quotient (IQ) and psychosocial functioning in 79 children born SGA at the start, and after 2 and 8 years of GH therapy, and addresses the associations with head circumference. Mean age at start of therapy was 7.4 years; mean duration of GH treatment was 8.0 years. In 2001, 91% of children born SGA had reached a normal height (> -2.0 standard deviation score [SDS]). Block-design s-score (Performal IQ) and Total IQ score increased (p < 0.001 for both indices) from scores significantly lower than those of Dutch peers at the start of therapy (p < 0.001) to scores that were comparable to those of Dutch peers in 2001. Vocabulary s-score (Verbal IQ) was normal at the start of therapy and remained so over time. Externalizing Problem Behaviour SDS and Total Problem Behaviour SDS improved during GH therapy (p < 0.01-0.05) to scores comparable to those of Dutch peers. Internalizing Problem Behaviour SDS was comparable to that of Dutch peers at the start of therapy and remained so, whereas Self-Perception improved from the start of GH therapy until 2001 (p < 0.001), when it reached normal scores. Head circumference SDS at the start of GH therapy and head growth during GH therapy were positively related to all IQ scores (p < 0.01), whereas neither were related to height SDS at the start of, or to its improvement during, GH therapy. A significant improvement in height and head circumference in children born SGA was seen after only 3 years of GH therapy, in contrast to randomized SGA controls. In conclusion, most children born SGA showed a normalization of height during GH therapy and, in parallel to this, a significant improvement in Performal IQ and Total IQ. In addition, problem behaviour and self-perception improved significantly. Interestingly, Performal, Verbal and Total IQ scores were positively related to head circumference, both at the start of, and during, GH therapy; head circumference increased in GH-treated children born SGA, but not in untreated SGA controls. These results are encouraging but also warrant confirmational studies and further investigations into the effects of GH on the central nervous system.     

Sequelae of syndrome X in children born small for gestational age

OBJECTIVE: Low birth weight is associated with the presence of syndrome X in adults. We studied the components of this syndrome in prepubertal children born SGA (small for gestational age) and children born AGA (appropriate for gestational age). METHODS: Twenty-nine SGA children, age (mean +/- SD) 9.1 +/- 1.1 years and 24 AGA children, age 9.0 +/- 1.1 years were studied. Fasting serum lipid concentrations were determined. A hyperinsulinemic euglycemic clamp was performed to measure insulin sensitivity. Ambulatory monitoring was performed to obtain 24-hour recordings of blood pressure. RESULTS: Prepubertal SGA children are less insulin sensitive and have a higher nighttime systolic blood pressure (SBP) after correction for BMI than children born AGA. No differences were found in lipid concentrations between the 2 groups. CONCLUSIONS: Not all components of syndrome X can yet be found in 9-year-old children born SGA; follow-up of this cohort is required.     

Hyperinsulinemia in pre- and post-pubertal children born small for gestational age

BACKGROUND: Reduced fetal growth is a potential risk factor for development of metabolic abnormalities in later life. The relationship between low birthweight and impaired glucose tolerance, type 2 diabetes and insulin resistance in adulthood has been well documented. PURPOSE: Assuming that fetal undernutrition is associated with insulin resistance in middle age, we elected to study whether this process may already be present in young adults and adolescents born small for gestational age (SGA). SUBJECTS AND METHODS: Children born in Vall d'Hebron Hospital Infantil, Barcelona, between 1986 and 1989 and between 1978 and 1983 with birthweights below the third centile for the local standard values, were invited to participate in the present study. Of those, 51 (22 girls and 29 boys) were pre-pubertal with 9.4 +/- 0.2 years of age and 49 (29 girls and 20 boys ) were post-pubertal, with 17.3 +/- 0.3 years of age. All patients underwent a standard, 2-hour oral glucose tolerance test. Insulin and glucose responses were compared with our previously published data in control children with normal birthweight. RESULTS: The insulin response at 30 min after glucose load was significantly higher (p < 0.001) in pre- and post-pubertal girls and boys formerly SGA than in controls. In addition, the girls also had a higher insulin response at 60 and 120 min. Mean serum insulin (MSI), the area under the insulin curve during the glucose challenge, was statistically increased in pre- and post-pubertal boys and girls born SGA when compared to controls. CONCLUSION: The presence of high insulin levels after an oral glucose challenge in children and adolescents born SGA might be considered as an early marker of subsequent insulin resistance in adulthood. Furthermore, our population offers the opportunity to study the natural course of hyperinsulinemia and its outcome. Follow-up of this cohort may be helpful in distinguishing a subset of young children and adolescents in whom therapeutic intervention could be done.     

Food intake of children with short stature born small for gestational age before and during a randomized GH trial

Parents of short children born SGA often report that their children have a serious lack of appetite and a low food intake. In this study we investigated food intake, by using a standardized 7-day food questionnaire, in 88 short SGA children before start of GH treatment. The intake was compared with the recommended daily intake (RDI) of age-matched children. We also compared the food intake of GH-treated children (n=62) with randomized controls (n=26) after 1 year of GH treatment. In addition, we evaluated the effect of food intake and GH treatment on body composition and serum levels of IGF-I, IGFBP-3 and leptin. Our study shows that caloric intake, fat and carbohydrate intake of short SGA children aged 5.9 (1.6) years was significantly lower compared to the RDI for age-matched children. One year of GH treatment resulted in a significant increase of caloric, fat, carbohydrate and protein intake compared to baseline. Compared to randomized controls, caloric, carbohydrate and protein intake increased significantly after 1 year of GH treatment. Short SGA children had significantly lower SDS scores for LBM, fat mass, skinfold (SF) and BMI compared to age-matched references. They also had significantly lower serum IGF-I, IGFBP-3 and leptin levels. GH treatment resulted in a significant increase of height, LBM, BMI, IGF-I and IGFBP-3 SDS and a significant decrease of SF SDS and leptin SDS. In conclusion, our study shows that short SGA children have indeed a lower food intake than age-matched controls. During GH treatment the food intake increased significantly compared to baseline in contrast to the randomized control group.     

Effect of different growth hormone dosages on the growth velocity in children born small for gestational age

To assess whether short-term growth hormone (GH) treatment can improve the linear growth in children who were born small for gestational age (SGA), we started a randomized multicenter trial in 26 age- and sex-matched prepubertal children born SGA. During the 1st year of GH therapy, all children received GH 0.23 mg/kg/week, then during the 2nd year, 13 children received the same dose (group A), and in the other 13 children, the dose of GH was doubled, i.e., 0.46 mg/kg/week (group B). During the 1st year of therapy, the growth velocity significantly (p<0.0001) increased in all patients. During the 2nd year, group A showed a significant decrease of the growth velocity (p<0.015), whereas group B maintained the growth rate. The height in group A children significantly increased during the 1st and the 2nd year of GH therapy (p<0.000002 and p<0.000001, respectively), reaching the normal range in 8 out of 13 children at the end of 2 years of GH therapy. The height in group B children significantly increased during the 1st and the 2nd year of GH therapy (p<0.000001 and p<0.000001, respectively), reaching the normal range in all 11 children who completed the GH therapy. The height gain was similar in groups A and B treated with the same GH dosage during the 1st year of therapy. A greater increase in height gain was found in children of group B treated with the higher GH dosage during the 2nd year of therapy as compared with group A (p<0.02). Significant increases in insulin-like growth factor I (p<0.0001), acid-labile subunit (p<0.0002), and bone/chronological age ratio (p<0.0001) were found after the 1st year of GH therapy, but no significant changes were observed during the 2nd year, independently of the GH dose. In conclusion, the height velocity of children born SGA significantly increases during the 1st year of GH therapy, diminishes, but can decrease during the 2nd year, if the GH dosage is not raised.     

Hormonal regulation of postnatal growth in children born small for gestational age

Children born small for gestational age (SGA) are at high risk of permanent short stature, with approximately 10% continuing to have stature below the third centile throughout childhood and adolescence and into adulthood. The mechanisms involved in catch-up growth, and those that prevent catch-up growth, are still unknown. To date, no reliable anthropometric or endocrine parameter predictive of postnatal catch-up growth has been identified. However, subtle abnormalities in the growth hormone-insulin-like growth factor axis, the hypothalamic-pituitary-adrenal axis and thyroid function have been described, and a mechanism involving intrauterine programming of hypothalamic-pituitary function has been proposed.     

Visfatin levels in prepubertal children born small or large for gestational age

Children born small (SGA) or large (LGA) for gestational age are prone to develop insulin resistance (IR) during childhood. Visfatin, a hormone with insulin-mimetic actions, has been associated with IR. This study was designed to examine whether serum level of visfatin is correlated with metabolic indices of IR, in prepuberty in association with the intrauterine growth pattern. The following parameters were evaluated at a mean age of 6.5±1.2 years in 155 prepubertal children born appropriate for the gestational age (AGA) (n=63), or SGA (n=42), or LGA (n=50): serum levels of visfatin, adiponectin, leptin, fasting glucose (G(F)) and insulin (I(F)), the homeostasis model assessment IR index (HOMA-IR), plasma lipids, anthropometric indices at birth and the time of evaluation, and obesity indices [waist circumference (WC), body mass index (BMI) and skinfold thickness]. The mean serum level of visfatin was lower in the SGA than in the AGA and the LGA children (9±5.2 vs. 11.8±5.1 and 12.7±5.6?ng/ml, respectively, p<0.01). Girls had lower visfatin levels than boys (10.4±4.3?ng/ml vs. 12.5±6.7?ng/ml, p<0.05). Visfatin was not correlated with IR indices. In multiple regression analysis visfatin level was positively correlated with birth weight z-score (t=2.56, beta=0.24, p<0.01) and crown to heel z-score (t=2.46, beta=0.22, p=0.014), independent of age, gender, maternal weight before pregnancy, maternal weight gain during pregnancy, BMI z-score, WC z-score, serum leptin and adiponectin, and HOMA-IR. In conclusion serum visfatin level was lower in prepubertal SGA children but not correlated with IR indices. Low birth weight was an independent predictor of visfatin level.     

Psychosocial functioning of adolescents with idiopathic short stature or persistent short stature born small for gestational age during three years of combined growth hormone and gonadotropin-releasing hormone agonist treatment

AIM: To examine psychosocial functioning of medically referred adolescents with idiopathic short stature (ISS) or persistent short stature born small for gestational age (SGA) during 3 years of combined growth hormone (GH) and gonadotropin-releasing hormone agonist (GnRHa) treatment. METHODS: Thirty-eight adolescents participated in a controlled trial with GH/GnRHa treatment or no intervention. Each year the adolescents and their parents completed questionnaires and structured interviews. Multilevel analysis was used to analyze data. RESULTS: The adolescents of the treatment group showed a worse outcome than the adolescents of the control group on 3 of 16 variables: perceived competence of scholastic (p < 0.01) and athletic ability (p < 0.05) and trait anxiety (p < 0.05). Adolescents in both the treatment and control groups perceived improved current height (p < 0.001) and self-appraisal of physical appearance (p < 0.05). The parents did not report changes in their children during treatment. CONCLUSION: The observation of some adverse psychological consequences as experienced by the adolescents indicates that it is useful to monitor psychosocial functioning during a combined GH/GnRHa treatment in adolescents with ISS or SGA. It is uncertain whether the hypothesized positive effects of the expected gain in final height by adulthood can sufficiently counterbalance possible short-term negative effects.